Source : Webster's Revised Unabridged Dictionary (1913)

Arthropoda \Ar*throp"o*da\, n. pl. [NL., fr. Gr. 'a`rqron joint
   + -poda.] (Zo["o]l.)
   A large division of Articulata, embracing all those that have
   jointed legs. It includes Insects, Arachnida, Pychnogonida,
   and Crustacea. -- {Ar*throp"o*dal}, a.

Source : WordNet®

Arthropoda
     n : jointed-foot invertebrates: arachnids; crustaceans; insects;
         millipedes; centipedes [syn: {phylum Arthropoda}]